I have 2 columns A and B containing these values in sheet 1.

Teamleader Teammembers
John A
Derick B
John C
Derick D

In sheet 2 i will be just entering the team leaders name and I want a
formula in only in 1 cell that would pull up the corresponding team members
names to appear vertically.

ie: If I enter John in sheet2 Cell A1 then B1 and B2 should autopopulate
with value "A" & "C"

Any help is appreicated, thanks in advance.